Design for Living

May 5, 2007

How do you design a city from the ground up in a way that makes sense environmentally and economically? This article in Wired magazine about the creation of Dongtan, a brand-new metropolis on an island in the mouth of the Yangzte River, a project devised by the engineering firm Arup, points the way to a planned city that actually gets greener as it gets bigger:

Their first decision was big. Dongtan needed more people. Way more. Shanghai’s planning bureau figured 50,000 people should live on the site — they assumed a green island should not be crowded — and the other international architects had agreed, drafting Dongtan as an American-style suburb with low-rise condos scattered across the plot and lots of lawns and parks in between. “It’s all very nice to have little houses in a green field,” Gutierrez says. But that would be an environmental disaster. If neighborhoods are spread out, then people need cars to get around. If population is low, then public transportation is a money loser.

But how many more people? Double? Triple? The team found research on energy consumption in cities around the world, plotted on a curve according to population density. Up to about 50 residents per acre, roughly equivalent to Stockholm or Copenhagen, per capita energy use falls fast. People walk and bike more, public transit makes economic sense, and there are ways to make heating and cooling more efficient. But then the curve flattens out. Pack in 120 people per acre, like Singapore, or 300 people, like Hong Kong, and the energy savings are negligible. Dongtan, the team decided, should try to hit that sweet spot around Stockholm.

Next, they had to figure out how high to build. A density rate of 50 people per acre could mean a lot of low buildings, or a handful of skyscrapers, or something in between. Here, the land made the decision for them. Dongtan’s soil is squishy. Any building taller than about eight stories would need expensive work at the foundation to keep it upright. To give the place some variety and open up paths for summer wind and natural light, they settled on a range of four to eight stories across the city. Then, using CAD software, they started dropping blocks of buildings on the site and counting heads.

The results were startling. They could bump up Dongtan’s population 10 times, to 500,000, and still build on a smaller share of the site than any of the other planners had suggested, leaving 65 percent of the land open for farms, parks, and wildlife habitat. A rough outline of the city, a real eco-city, began to take shape: a reasonably dense urban middle, with smart breaks for green space, all surrounded by farms, parks, and unspoiled wetland. Instead of sprawling out, the city would grow in a line along a public transit corridor.

But how to generate power for the city? Here’s where it gets even more interesting:

Next, the city needed green power. But the planning process grew complicated. A city is a huge mess of dependent variables. The right recycling facility can turn trash into kilowatts. The right power plant can convert waste energy into heat. The right city map will encourage people to walk to the store instead of drive. “These are things people don’t normally plan together,” Gutierrez says.

They needed something they started calling an “integrated resource model,” something to show how each change would ripple across the city plan. So Arup’s programmers wrote software that stitched together databases detailing the inputs (say, the cost of photovoltaic panels) and outputs (electricity generated per panel) of any facility, process, product, and human activity on the island. If the team moves an office park a mile, the software can recalculate average walking distances for commuters, figure how many people will drive or take public transit instead of walk, and then add up the ultimate change in energy demand. Maybe more important, the software makes it easy to spot places where one process creates waste that another process could recycle. “Design was very trial-and-error,” Gutierrez says. “The only thing we knew was that we wanted to connect things, to create virtuous cycles.”

A power scheme started to take shape. Dongtan’s plant would burn plant matter to drive a steam turbine and generate electricity. What to burn, though? They could have planted miscanthus, a tall, feathery grass. It sprouts fast and burns clean. But if Arup planted miscanthus fields, it would sacrifice lots of land to a single purpose. Then it struck them: rice husks. China already grows mountains of rice, and farmers just trash the husks. Dongtan could take a useless byproduct and use it to light the city.

Instead of building the plant far away and out of sight, Arup would put it up near the city center, capture waste heat, and pipe it throughout the town. With good insulation and smart design, the plant could heat and cool every building in Dongtan. “We can get something like 80 percent efficiency in our fuel conversion,” says Chris Twinn, the Dongtan team’s energy chief. “The Prius is probably only 20 percent efficient. The rest is wasted. Why are we satisfied with that?”

Between biomass, a big wind farm, and numerous tiny contributions to the grid — including photovoltaic panels and small wind turbines — Arup figured Dongtan could get 60 percent of its energy from renewable sources when the city opened in 2010, and 100 percent within 20 years.

At this pivotal moment in history, the Bush response to any challenge boils down to one of the three Bs: Buy it, bomb it or bullshit it. When it comes to environmental matters, “bullshit it” is in full effect. Instead of looking for innovative approaches that embody the spirit of enterprise and capitalism, Bushie conservatives like Glenn Beck give us tired spin points and discredited non-arguments.

Dongtan is a rare instance of being able to design something from the ground up. Most of the problems associated with climate change and environmental degradation will have to be dealt with in other ways.

But what I love about this article is the way it shows that out there in the larger world, beyond the ring of back-scratching crony capitalists, petrochemical flacks and ideological clowns that have America in a hammerlock, people are still thinking and trying new things. May that spirit return here, sometime soon. Please.


2 Responses to “Design for Living”

  1. Scott Stiefel Says:

    That’s “Bushite.”

  2. Ron Fischer Says:

    While there are some good ideas in the quoted article, two things make me suspicious about the validity of the overall design.

    First, rice husks, while surely widely available in China, have an extremely low energy density. That is, for a given weight of this stuff you need an enormous volume of it to gain an appreciable amount of energy. Given a “centrally located” powerplant this means many, many trucks travelling hundreds of miles to transport bags of fluffy rice husks. The US corn ethanol industry faces a similar problem. This is why there are so many distilleries: they need to be close to the source of corn for it to make economic sense. Same problem exists for cellulosic (wood) ethanol.

    Second, Prius efficiency is much (much) higher than 20%.

    No real engineer would make mistakes like these. They’re fundamental. While it sounds like they did their homework regarding appropriate density, overall this sounds like a bunch of non-technical architectural grads making up stuff in a vacuum.

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